The overall objective of the proposed SBIR program is to design, manufacture, and evaluate a high-speed, low-damage, machining center for fabrication of Dental restorations in the Dental office or laboratory. This new method for fabrication of Dental restorations based on computer aided design and computer aided manufacturing (CAD/CAM) has revolutionized Dentistry during the past decade. These systems are currently used to fabricate ceramic crowns and other Dental structures. While the CAD/CAM restorations have proven to be more reliable than those fabricated by traditional methods, the 10-year survival rate is still less than 90%. Furthermore, these systems cannot be used for machining of restorations made from harder ceramics such as zirconia. The proposed machining center will be designed with an innovative integrated air-driven, high-speed, precision spindle/motor assembly to allow high machining rates while ensuring low potential for machining damage: thus, enabling rapid fabrication of low-damage Dental restorations by machining. Phase I plan includes design, fabrication, and testing of an air-driven, high-speed, motor-spindle assembly operating at ultra-high speeds; and machining data obtained on two machinable Dental ceramics and partially stabilized zirconia in a full factorial design of experiments showing reduced machining damage as compared to the current practice. The data on machining rates and surface/subsurface damage will be compared with similar data already published by the applicant from a previous NIDCR Program Project Grant on machining with a high-speed Dental handpiece. The aim of these experiments is to test the hypothesis that high-speed machining reduces the propensity for generation of machining damage. While high-speed machining has been implemented for grinding of industrial ceramics, including zirconia, such an approach is yet to be considered for Dental CAD/CAM systems. [unreadable] [unreadable] [unreadable]